Autistic and neurotypical adults process body parts similarly in the brain

Autism spectrum disorder (ASD), a neurodevelopmental condition, is often associated with difficulties in social communication and repetitive behavior. Previous research reveals that people with ASD often find it challenging to interpret intentions from body language and have difficulty recognizing faces and emotions, which may contribute to their social communication problems. Scientists speculate that these challenges might arise from differences in how the brain perceives faces and body parts, i.e., how individuals with ASD represent the human body. However, until now, no study had clearly mapped how body parts are represented in the brains of adults with autism or whether that organization differs from normal or typically developing (TD) adults.

In a detailed neuroimaging study involving adults in Japan, researchers addressed this knowledge gap by examining how ASD represents body parts in the brain. This study was published in Volume 3 of the journal Imaging Neuroscience on 5 June 2025. A team of researchers, including Professor Hirotaka Kosaka from Fukui University, Professor Rieko Oso, and Guest Junior Researcher Yuko Okamoto from Waseda University, was led by Assistant Professor Yuto Kurihara from the Faculty of Human Sciences, Waseda University, Japan, and used functional magnetic resonance imaging (fMRI) to compare brain activity patterns in adults with ASD and TD adults as they viewed images of body parts. "Our goal was to test whether the lateral occipitotemporal cortex (LOTC)-a brain region known to represent visual information about different body parts in a clustered way-functions differently in adults with autism," says Kurihara.

The research team recruited 23 adults with ASD and 23 TD adults. Each participant underwent fMRI scanning while viewing grayscale images of eight body parts (e.g., hands, legs, face), the whole body, and chairs as a control object. Participants completed a 1-back task, pressing a button whenever an identical image appeared twice in a row, to ensure attention during the scan. The fMRI data showed that both groups activated the LOTC when viewing whole-body images. Importantly, there were no significant differences in the size or strength of this activation between the ASD and TD groups, indicating similar basic visual responsiveness.

To look deeper, the researchers used an advanced analysis method to understand how the brain organizes information about different body parts. They found that in both groups, the LOTC grouped body parts into three categories: action effectors (hands, feet, arms, and legs), non-effectors (chest and waist), and facial parts (upper and lower face). "These results suggest that adults with autism perceive visual body information in much the same way as neurotypical adults," says Kurihara. "These challenges long-standing assumptions that differences in body-related perception contribute to social difficulties in ASD." To make sure the results were solid, the team also tested whether brain activity patterns could accurately distinguish between different body parts. Again, both groups performed similarly. The researchers also analyzed whether brain patterns were linked to individual differences-such as autism symptom severity or sensory traits-but found no strong connections. Interestingly, earlier studies in autistic children showed different brain responses in the LOTC. But Kurihara's team thinks this may change with age. "Children with autism may see body-related information differently, but those differences seem to fade as they grow up," Kurihara explains.

Overall, the study shows that while people with autism may struggle to read emotions or intentions from gestures or expressions, the challenge may lie in interpreting these signals-not in seeing them differently. This insight could help shape more effective interventions, such as teaching social understanding or imitation, especially for adults.

"Our brains keep learning," Kurihara says. "This study gives us hope-and a reason to keep improving how we support people with autism at every stage of life."